init-storage: Skip fs relabel w/o SELinux

If SELinux support is not available or enabled, attempting to relabel
files will fail.

overlay/usr/libexec/init-storage

@@ -89,6 +89,9 @@ partition_number() {
 }
 
 relabel_all() {
+    if [ ! "$(command -v selinuxenabled)" ] || !selinuxenabled; then
+        return 0
+    fi
     selinuxtype=$(. /etc/selinux/config && echo ${SELINUXTYPE})
     find "${tmpdir}" | \
     setfiles \